The currently used fire extinguishing agents are fire foam, dry powder extinguishing agent, carbon dioxide extinguishing agent, carbon tetrachloride extinguishing agent, etc. They are usually packed in special extinguishers for use. Depending on the properties of the material on fire, different extinguishing agents are selected. The extinguishing mechanism of the above mentioned extinguishing agents are based on a physical principle to isolate the fire source from air by a protection layer formed by foam, powder, or inert gases, provided by extinguishing agents. It is effective to extinguish stable fire in a small area caused by classes B and A materials when wind speed is not very high. However, for unstable fire under a condition of high wind speed, for example, the wind power is over grade 6, i.e., the wind speed is in the range of about 10.8-13.8 m/s, it is difficult or impossible to achieve the anticipated result. If fires are caused by flammable liquids, such as fuel oils, edible oils, organic solvents, or oil and grease containing materials, because of the unstable combustion, the large quantity energy produced, the high spreading and diffusing abilities, and the high temperature of liquid surface (&gt; 300.degree. C.), the currently used fire retarding and extinguishing agents can not be used to extinguish the fires with enough speed and effectiveness. Especially, when the fire occurs on a fuel tank of a vehicle by mechanical collision or traffic accident, the fire expands so swiftly and violently that a strong explosion will happen before the utilization of fire extinguishing equipment, resulting in fire hazard, casualties, and serious economic loss. Besides, the explosion of fuel tanks also can be caused by the static sparks formed in the movement of vehicles, for which the ordinary extinguishing materials are virtually worthless.
For extinguishing fires caused by flammable liquids, such as crude oils, fuel oils, edible oils, organic solvents, etc., and oil and grease containing materials, a variety of chemical fire retarding and extinguishing materials have been developed and produced, such as halogen substituted hydrocarbons, phosphonates, inorganic compounds, etc. However, these chemical fire retarding and extinguishing materials are usually used as additives in polymer engineering materials. Only a few of these materials can be used as fire extinguishing materials, such as fluoro-bromo-alkanes, which, however, are hardly to be used extensively because of the expensive cost and the destruction effect to the ozonosphere. Moreover, since these materials are water insoluble, it is very difficult to prepare a fire retarding and extinguishing agent using an aqueous solvent.